Process of making dialkyl-barbituric acid.



UNTTED STATES PATENT MAX l-h\'(%lCL.\l.-\NN, OF ELBERFELD, GERMANY, ASSIUNOR TO FARBEN- FARRIRICN OF ELBERFELD OO., OF NIUY YORK, N, Y., A CORPORATION OF NEH YORK.

Patented April 18, 1905.

OFFICE.

PROCESS OF MAKING DlALKYL-BARBITURIC ACID.

SPECIFICATION forming part of Letters Patent N0. 787,360, dated April 18, 1905.

Application filed January 5, 1905. Serial No 239,788.

Be it known that 1, Max ICNHRLAIAXN, residing at l llberfeld, lermany, (assignor to the i l*,\nm:.\'i .\m:iklax or linnlmnnnn (o., of New Yorkd have invented a new and useful lmprovement in Processes of lreparing l)ialk vl l'hn-bituric Acids: and ldo hereby declare the following to be an exactand clear description of my invention.

.\l v invention relates to a new process for the production of dialkvl-barbituric acids (fli-li-trioxy-S-dialk vlpyrimidins) having the following general formula:

(h meaning alkvl radicals) which bodies possess valuable therapeutic, especiallysoporilic, properties. of these compounds consists in lirst condensing dicvaiuliamid with dialkvlated malonitrils of the general formula:

y means of alkaline condensing agents and r then splitting off the cyanimino group and the imino groups and replacing them by oxygen in 2- land 6- position from the resulting i-cvanimino-t-li-diimino-5-dialkylpyrimidins of the general formula:

The process for the preparation ing mixture is heated for four to live hours to [20" Centigrade in an autoclave. The alcohol is distilled ofl', and the resulting residue is dissolved in waterand neutralized by means of dilute lrvdrochloric acid. A fter a recrystallization from hot water the new body is obtained in the shape of crystals melting at 270 centigrade. For the saponilication ten parts of the 2-c vanimino-l;-(5-diimino-5-dieth vlpyrimidinthus produced are heated with thirty parts of a fort v-per-cent. sulfuric acid for three hours to 110* centigrzulc. After cooling it is filtered oil and the diethyl-barbituric acid thus precipitated is purilied by a recrystallization from water.

Instead of an alcoholic solution of potassium ethylate other alkaline condensing agents-such as solid alkaline alcoholates, sodium amid, or the likes-can be employed.

The saponilication can also be carried out with other acids, such as hydrochloric acid, oxalic acid, or the like.

The process proceeds in an analogous manner for the production of other dialkyl-barbituric acids, such as the dipropyl or the dimetlrvl-barl)ituric acid, or the like.

llaving now described my invention and in what manner the same is to be performed, what I claim as new, and desire to secure by Letters latent, is

1. The process for the production ofdialkylbarbituric acids having the above-given general formula, which process consists in lirstcon- (lensing d icyandiam id with dialkylatcd malonitrils by means of alkaline condensing agents and then splitting off the cyanimino group and the imino groups in -land (5- position from the resulting Q-cyanimino--G-diimino- 5-dialkyl-pyrimidins by treatment with acids. substantially as hereinbefore described.

2. The process for the production ofdiethylbarbituric acid, which process consists in lirst condensing dicyandiamid with diethyl-mal0 nitril by means of alkaline condensing agents, and then splitting off the cyanimino and the imino groups in 2- -t and (5- position from the resulting 2- cyanimin0-4-6-diin1ino-5-diethylpyrimidin by treatment with acids, substantially as hereinbefore described.

3. The process for the production of diethylbarbituric acid, which process consists in first condensing dicyandiamid with diethyl-malonitril by means of potassium ethylate and then splitting off the cyanimino group and the imino groups in 2-, 4 and 6- position from the resulting Q-cyanimino-4=6-diimino-5-dietbyl IO pyrimidin by treatment with hot sulfuric acid, substantially as hereinbefore described.

In testimony whereof I have signed my name in the presence of two subscribing witnesses.

MAX ENGELMANN.

Witnesses OTTO Kome, PAUL HODEIGE. 

